not recognizing 2nd hard drive

I have 2 hard drives. I basically copied all data from one to the other so I could format my original hard drive. I thought this would clean up my machine along with I didn't like that my first hard drive was partitioned. Well after formating my original hard drive, I can't display my second hard drive. When I go into bios I see a second drive but shows a size of 8 meg instead of 20 meg. How do I get my second hard drive back with out loosing the data I backed up onto it ? HELP.